The personal computer has become the engine of efficiency in the office environment, enabling a wide range of functions to be more easily achieved, including word processing, report generation, calendar date reminders, customer billing and other important organizational functions. The office environment also depends heavily on the telephone for communications, and typically the telephone and computer, while being located in the same environment, are not integrated and provide stand-alone, separate functions. Thus, the computer keyboard numeric keypad, which could be used for dialing telephone numbers, is not arranged for such an application.
Attempts have been made at electronically integrating the telephone and keyboard functions, and one example of the prior art in this area is disclosed in U.S. Pat. No. 4,860,342 to Danner. The computer serves as an interface between a keyboard and a telephone controller, and the telephone controller can be activated by depression of a designated keyboard key. Control is then switched from the application routine running on the computer, and the telephone controller establishes a telephone connection. After this, the keyboard inputs are interpreted by the computer as normal telephone dialing commands, rather than as inputs or instructions to the existing application routine. Once the telephone dialing commands have been entered, program control returns to the previously running application routine.
Another prior art reference is provided in the article entitled "Meridian M4020: Integrated terminal for today and tomorrow", authored by G. Grantham and published in Telesis, Vol. 2, 1985. The M4020 terminal is a workstation incorporating a telephone and a keyboard, and the telephone functions are handled by a remotely located host processor which receives messages via a local area network (LAN) link. Once the host has established the telephone connection, it sends a message to an internal card in the terminal to turn on the telephone speaker/microphone.
As can be seen from a review of the prior art, previous attempts at effecting communication between the telephone and the keyboard were achieved using the computer which is interposed between them. Thus, the computer must be provided with hardware to enable it to establish the connection to the telephone lines, and since this hardware is not included in a standard personal computer, a modification is needed. While such hardware modifications can be achieved by the insertion of plug-in printed circuit boards in the computer, often the user is reluctant to perform such modifications, since not all users possess the requisite familiarity with the computer.
Another approach to providing a telephone-computer interface has been demonstrated by a product commercially sold and available from owners of the present invention, Integrated Technology, Inc., Teaneck, N.J., under the tradename Compuphone, which incorporates telephone capabilities in a specially-designed keyboard. Although the computer hardware needs no modification, this product requires replacing the existing keyboard, and therefore involves an additional upgrade cost factor for existing computer systems.
Thus, it would be desirable to provide an external telephone adaptor enabling connection of a telephone to a computer system, for computer control of telephone functions.